A circuit breaker is a device that protects the circuit by stopping the current when a current exceeding a specified value flows through the circuit, and used for opening and closing the normal load of the circuit and cutting off the fault current.
For example, the circuit breaker can be used in a switchboard that includes various electric devices including the breaker to operate or control a power plant, a substation, and so on, or operate a motor.
FIG. 1 is a perspective view schematically illustrating a breaker main body.
Referring to FIG. 1, the breaker main body 1 has a plurality of breaker terminals 10 (e.g., 10a, 10b).
In an example, an upper terminal 10a of a plurality of breaker terminals is a bus terminal, and a lower terminal 10b is a load terminal.
Meanwhile, FIG. 2 is a schematic view of a cradle to which a breaker main body is connected.
Referring to FIG. 2, the cradle 3 for connection with the breaker main body 1 (see FIG. 1) described above is shown, in which the cradle 3 is provided with a plurality of cradle terminals 20 (e.g., 20a, 20b).
In an example, an upper terminal 20a is a bus cradle terminal and a lower terminal 20b is a load cradle terminal.
As described above, a plurality of breaker terminals 10 (e.g., 10a, 10b) (see FIG. 1) are connected to a plurality of cradle terminals 20 (e.g., 20a, 20b).
Accordingly, the circuit breaker is configured, including therein the breaker main body 1 having a plurality of breaker terminals 10 (e.g., 10a, 10b) and the cradle 3 having a plurality of cradle terminals 20 (e.g., 20a, 20b).
FIGS. 3 and 4 are side views illustrating a relationship between the breaker main body and the cradle before and after the breaker main body is connected to the cradle. Referring to FIG. 3 illustrating the breaker main body 1 before being connected to the cradle 3, the breaker main body 1 is configured to be movable toward the cradle 3 fixed in position.
In an example, the bus cradle terminal 20a of the cradle 3 is formed in the same position as the bus breaker terminal 10a of the breaker main body 1, and the load cradle terminal 20b of the cradle 3 is formed in the same position as the load breaker terminal 10b of the breaker main body 1.
FIG. 4 illustrates the breaker main body 1 moving in an insert direction W to be connected to the cradle 3.
That is, FIG. 4 shows a plurality of breaker terminals 10 (e.g., 10a, 10b) provided in the breaker main body 1 being connected to a plurality of cradle terminals 20 (e.g., 20a, 20b) provided in the cradle 3.
FIG. 5 is a view illustrating, in enlargement, a detailed configuration of a related terminal.
Referring to FIG. 5, the related breaker terminal 10 (including the bus breaker terminal 10a and the load breaker terminal 10b) includes a terminal body 11, and contacts 13 coupled to upper and lower portions of the terminal body 11.
The related breaker terminal 10 includes the contacts 13 connectible to cradle terminals (that is, to any of 20a and 20b in FIG. 4).
In particular, a pin fixing member 17 is simultaneously fastened through the terminal body 11 and the contact 13 to fix the contact 13.
Further, a contact spring 15 is provided between the contact 13 on one side (e.g., upper side) and a head of the pin fixing member 17 to impart a predetermined elastic force.
FIGS. 6A. 6B and 6C are views illustrating a related terminal moving in a direction toward the cradle terminal for connection.
Referring to FIG. 6A, the breaker terminal 10 of the breaker main body is moved toward the cradle terminal 20 of the cradle.
In an example, the breaker terminal includes a bus breaker terminal 10a and a load breaker terminal 10b, and the cradle terminal 20 includes a bus cradle terminal 20a and a load cradle terminal 20b. 
Meanwhile, curved surface portions 14 are provided at front end portions of the related contacts 13 such that an insert part 21 of the cradle terminal 20 is moved along the curved surface portions 14 to be smoothly inserted into a gap defined between the contacts 13.
That is, interferences and impacts are not suffered when the cradle terminal 20 is inserted in between the contacts 13.
Referring to FIGS. 6B and 6C, the insert part 21 of the cradle terminal 20 is inserted by a predetermined length along the curved surface portions 14 of the contacts 13.
Then, the curved surface portions 14 press both sides of the inserted cradle terminal 20 to securely maintain the contact state therebetween.
To that end, the gap between the curved surface portions 14 of the contacts 13 is formed smaller than the thickness of the cradle terminal 20.
Meanwhile, as illustrated in FIGS. 6A to 6C, the circuit breaker may be provided in a transversal arrangement of the circuit breaker, in which the breaker terminal 10 of the breaker main body and the cradle terminal 20 of the cradle are connected to each other in a mutually facing manner. Alternatively, a longitudinal arrangement of the circuit breaker may be contemplated.
FIG. 7 illustrates a longitudinal arrangement of the circuit breaker.
Referring to FIG. 7, a plurality of breaker terminals 10 are arranged in a straight line at equal gap on the breaker main body 1, and cradle terminals 20 disposed in front of each breaker terminal 10 are connected thereto.
Thus, in this arrangement, the respective cradle terminals 20 are connected to the respective breaker terminals 10 upon the breaker main body 1 being moved in the insert direction W.
Meanwhile, referring to the encircled section of FIG. 8 shown in enlargement, the structure of the curved surface portions 14 of the related contact 13 causes a problem in which the cradle terminal 20 cannot pass through the side surfaces of the curved surface portions 14 and the curved surface portion 14 and the cradle terminal 20 collide against each other at certain region P.
In other words, a gap c (see FIG. 9) between the curved surface portions 14 of the related contacts 13 is formed narrower than the thickness t (see FIG. 8) of the cradle terminal 20.
Therefore, in the transversal arrangement of the circuit breaker, insertion of the cradle terminal can be facilitated, using a certain shape of the curved surface portions 14.
However, as shown in FIG. 8, since the cradle terminal 20 cannot be fit into the curved surface portions 14 having the gap c (see FIG. 9) narrower than the thickness t of the cradle terminal 20, the longitudinal arrangement of the circuit breaker particularly has a problem in connecting the breaker terminals 10 and the cradle terminals 20.
For related technology of the present disclosure, Korean Patent No. 10-1309040 discloses a circuit breaker.